Sulfur containing organo-organo-oxysilane

ABSTRACT

THERE ARE PREPARED SULFUR CONTAINING ORGANO-ORGANOOXYSILANES OF THE FORMULA A-X-Z WHERE A IS   N=C-S-   R-S-, RO-CS-S-, RS-CS-S-, R1-CS-S-, WHERE R AND R1 ARE UNIVALENT ORGANIC RESIDUES, X IS A DIVALENT ORGANIC RESIDUE, Z IS -SIR&#34;(OR&#39;&#39;)2; -SI(OR&#39;&#39;)3 -SI(OR&#39;&#39;)2-O-SI(OR&#39;&#39;)3; -SI(OR&#39;&#39;)2-NH-SI(OR&#39;&#39;)3; -SI(OR&#39;&#39;)2-O-SI(OR&#39;&#39;)2-X-A; -SI(OR&#39;&#39;)2-NH-SI(OR&#39;&#39;)2-X-A WHERE R&#39;&#39; AND R&#39;&#39;&#39;&#39; ARE ALKYL GROUPS OF 1 TO 12 CARNON ATOMS. THE COMPOUNDS ARE USEFUL AS ADDITIVES TO CROSSLINKABLE MIXTURES CONTAINING ORGANIC POLYMERS.

United States i Patented Mar. 19, 1974 U.S. c1. zen-41.5 A 14'Claims ABSTRACT on THEDISCLOSURE There are prepared sulfur containing organo-or-ganooxysilanes of the formula A-X--Z where A is R s 'Ro+-cs s-,- Rs cs-s+,-- R -CS-S.-"-,

where R and R are univalent organicresidues,- Xqisa atoms. The compounds are us'efulas additives toflcro p linkable. mixtures containing organiclpolymergsa The invention relatesto useful sulfur containingorg'anoorganooxysilanes exerting two important functions-" and their main rubber mixtures.

'The addition reaction. of silicon compounds'containing' atleast one hydrogen atom bound to silicon;to..non'a'r'o-" matic carbon to carbon double and triple bonds is knownin the literature. This addition reaction-proceeds' for example from trichlorosilane and a double bond containing substance according to the followingcquation;

As catalysts for this reaction platinum compounds havemany advantages, for example there can be used diehlor'oplatinum ('IV) acetyl "acetonatei (see German Auslegeschrift 1,271,712 and corresponding Knor-re et a1. 'U.S.=

Pat. 3,470,225 the entire disclosures incorporated by reference).

'If there are used for examplea ganic starting compounds the industrially easily available of which are hereby allyl halides the addition ofitrichlorosilane using the'.

above named special platinum containing catalysts proceeds according to the following equation to form genpropyl trichlorosilanes where is Cl,

3-halo-' I 55;. s the unsaturated'or-l The halogenorgano halosilanes formed can be reacted with various alcohols. Thereare formed halogenorgano organooxysilanes, for example using the above mentioned 7 3-halogenpropyltrichlorosilanes a reaction occurs according to the following equation where R is an organic group attached to the alcoholic hydroxyl group. There are formed accordingly 3-halogenpropyltrialkoxysilanes. The alkoxysilanes are also desigfiated as oxysfilanes (see Ullmanns Enzyklop'aldie der Technischen Chemie, vol. 15 (1964), p 762).

The halogenorgano-organooxysilanes formed from the reaction product of silicochloroform and a preferably lower monovalent alcohol which can' be added to unsaturated halohydrocarbons according to the equation H a)a )a In this reaction. also platinum compounds are required a ca l s v sulfur'containing organo-organooxysilanes of the invention are ;prepared by reaction of halogenorganoorganooxysilanes with organic sulfur compounds, preferably withmetal or ammonium salts. The reaction proceeds accordingto'the general equation Reaetion I is preferably carried out in solution, e.g. in inert organicv solvent. The solvent is preferably chosen so that the salt A-Me is soluble therein .while on the;

contrary the salt Me--Hal formed in the reaction is slightly soluble or insoluble therein. The precipitated salt MeHal is filtered ofl? and the sulfur containing organoorga'nooxysilane remains behind after removal of the solvent or it is recovered in pure form by vacuum distillation if it is not decomposed.

If the metal or ammonium salts of the starting compounds: in special cases are not available the transformation canxbecarried out in the presence of hydrogen halide acceptors according to the following general equation;

+Acceptora A-'-XZ+H- Hal-Acceptor (Examples of acceptors are tertiary amines such as triethylamine, tripropylamine, etc.)

In the general Equations I and following significance.

Me: ammonium, hydrocarbonfjsubstituted ammonium, e.g. tetramethyl ammonium, triethyl ammonium, diethyl ammonium, a metal of the alkali or alkaline earth metal group, e.g .sodiun 1, potassium, rubidium, cesium, barium,

lithe terms have the calciurii} strontium or'magnesium, as well as manganese, iron, cobalt, nickel, zinc, cadmium or copper in equiv-' alence to A, e.g. NaA or Ca(A Preferably Me signifies ammonium,-'-'sodium or'potassiiim- 1 Hal: a halogen of the group'of Cl, Brand I (i.e. halogen of atomic weight 35, 80 resp. 127.); preferably chlorine or bromine, (halogen of atomic weight 35 resp. 80).

X is a divalent hydrocarbon group, saturated or unsaturated, branched or straight chain, however, having" at least 3 carbonato'ms in the main chain, acyclic, cyclic with 5? 3 to 18 carbon atoms whose hydrogen atoms in a given can also be contains 1 to 3 carbon atoms), and in which the organic case can be substituted by fluorine, pseudohalogen (see a a t 4 N Rompps Chemisches worterbuch (1969), p. 707, e.g. U A

thiocyanate), phenyl, halophenyl (e.g. chlorophenyl or I I bromophenyl), alkyl or dialkylphenyl (in which the alkyl N HS residue X can -be interrupted by one or up to four heteroatoms (oxygen, nitrogen, sulfur and/or phosphorus) or R6 can form a heterocyclic group with these hetero atoms; SH preferably X is CH ,(CH CH (n is 1 to 15, l R

preferably 1 to 3). 10 N I I HS Hs N I N (b) R+ where R; and R are hydrogen or lower alkyl, e.g. alkyl 15 of 1 to 8 carbon atoms or phenyl.

In the Formulae b to d R indicates a univalenthydro- 1 carbon group, saturated or unsaturated, branched or a (lJ straight chain, acyclic or cyclic; a heterocyclic or hetero- H 1H6 aromatic group; all these respectively with 1 to 15 carbon atoms and 1 to 5 heteroatoms from the group of nitrogen, oxygen and sulfur. In the Formula e furthermore R 5 Q means N; H N- and 6 H R7 CH3 N- p 3 The first two named groups for R are particularly advantageous. wherein R2 and R3 Same different) are y g The various sulfur containing organo-organooxysilane alkyl 0f 1 t0 5 carbon atoms, y cycloalkyl With,5 10 compounds of the invention in general can be obtained 7 Carb atoms both together With the nitrogen atom according to Equations I and II by variation of the comform a ring having 5 to 8 atoms with up to one further 5 pound or the compound without nitrogen Oxygen Sulfur atom- Preferably R means ing a special synthesis for each new compound. The sulfur hydrocarbon p Saturated unsaturated, ethyl containing organo-organooxysilanes can be made industri-' ellically unsaturated, branched straight ,chain with 1 ally in a very favorable manner from inexpensive starting to 8 (Iafboh atoms hetelocyclic groulis with P to 3 materials. The industrial applications of these compounds nitrogen atoms and in a given case having Side chain 40 are therefore in a wide extent and in man'yfold ways thereon a sulfur atom as well as in a given case a merpossible p and/01' amino group, which in latter case can The sulfur containing organo-organooxysilanes are used be Substituted with lower alkyl o p alkyl of 1 to advantageously as vulcanizing agents in the crosslinking 8 carbon atomsor elastomers and as binding agents lbetween inorganic I fillers and organic polymers. Examples of elastomers inz; --SiR"(OR')z; si(0R')3; clude polyisoprene such as natural rubber, polyisoprene,

H I polybutadiene, butadiene-styrene copolymer, butadiene- I I acrylonitrile copolymer, terpolymers such as polymers of I v ethylene-propylene cyclooctadlene, ethylene-propylenenorbornadiene, ethylene propylene dicyclopentadiene,

wherein and R are the Same or different andhve etlgl'jlenelpropylene-cyclododecatriene, furthermore butyl ru er e c. 1 the followmg.slgmficance alkyl of 1 t lm. m Examples of compounds within the present invention preferably Z is include -Si(OCHa):, -Si(OCHCH:)a, si ocmcmcm)a. f i

Cm 3-th ocyanatopropyl tr methoxy silane, I g 3-th1ocyanatopropyl trlpropoxy silane, SKOGHICHlCHflCHfl) 1 I 3-thiocyanatopropyl diethoxy methyl silane,

0 3-thiocyanatopropyl tributoxy silane,

CH3 4-thiocyanatobutyl triethoxy silane, 6-thiocyan'atohe'xy1 triisopropoxy silane, K E 18-thiocyanatooctadecyl trimethoxy silane,

CH8 1,3-(3-thiocyanatopropyl)-1,1,3,3-tetramethoxy disiloxane, Preferably in the A portion of the molecule AXZ '5 1,3-(3-thiocyanatopropyl)-1,1,3,3-tetraethoxy disiloxane, the group R signifies 2-diethylamino4-mercapto-6-(3-triethoxysilyl propyl)- t thiotriazine, I CHCH Cmcmm I 2-dimethylaminol-mercapto-6-(4triisopropoxysilyl -0mcmcmcm; CH; CH=CH butYD'thwmazme I 1 a 2-amino-4-mercapto-6-(3-trimethoxysilyl propyl)- thiotriazine,

-N N NN NN N I LSJL; LNJI ESJL; HSlSJL; fi Z-tEISEEZLaEinO-e-merca tO-G-(S-tributoxysilyl amyl)- 2-phenyla'mino-4-mercapt0-6-(3-triethoxysilyl propyl)- s thiotn'azine,

2-butylamino-4-mercapto-6-(18-triethoxysilyl octadecyl)- thiotriazine, allylthiopropyl trimethoxy silane, pentadecenylthiopropyl trimethoxy silane, 2,4-dimercapto-6-(3-triethoxysilylpropyl)-thiotriazine, 2-mercapto-4-(3-triethoxysilyl propyl)-thiotriazine, 2-mercapto-4-(3-tripropoxysilyl propyl)-thiotriazine, 2-methyl-4-mercapto-6-(3-tributoxysilyl propyl) thiotriazine, 2-mercapto-5-(3-triethoxysilyl propyl)-thio-1,3,4-thiadiazole, 3-triethoxysilylpropyl-ethyl-xanthogenate, 3-trimethoxysilylpropyl-ethyl-xanthogenate, 3etripropoxysilylpropyl-ethylrxanthogenate, 3-triisopropoxysilylpropylethyl-xanthogenate, 3-tributoxysilylpropyl-ethyl-xanthogenate, 3 triethoxysilylpropyl-methyl-Xanthogenate, 3 trimethoxysilylpropyl-propyl-xanthogenate, 3-trimethoxysilylpropyl-isodecyl-Xanthogenate, 3-triethoxysilylpropyl-2-ethyl hexyl-Xanthogenate, 3-triethoxysilylpropylpentadecyl-xanthogenate, 3-triethoxysilylpropyl-allyl-Xanthogenate, 4-tributoxysilylbutyl-ethyl-xanthogenate, 18-triethoxysilyloctadecyl-methyl-xanthogenate, 1,3-(3-S-thiocarbomethoxypropyl)-1,1,3,3-tetramethoxy disiloxane, 1 1,-3-(-3-S-thiocarboethoxypropyl)-l,1,3,3-tetraethoxy disiloxane, 3-triethoxysilylpropyl-ethyl-thioxanthogenate, 3-tripropoxysilylpropyl-methyl-thioxanthogenate, 3-triethoxysilylpropyl-isobutyl-thioxanthogenate, 3-triethoxysilylpropyl allyl-thioxanthogenate, 1,3-(3-S thiocarbomethylmercapto propyl)-1,1,3,3-

tetramethony disiloxane, 3-triethoxysilyl-propyl-N-methyl-dithiocarbaminate, 3-trimethoxysilyl-propyl-N-ethyl-dithiocarbaminate, 3-tributoxysilyl-propyl-N-hexyl-dithiocarbaminate, 4-triisopropoxysilyl-butyl-N-octyl-dithiocarbaminate; 3-triethoxysilyl-propyl-N-allyl-dithiocarbaminate, 3 -dipropoxymethylsilyl-propyl-N-allyl-dithiocarbaminate, 3-trimethoxysilyl-propyl-N-allyl-dithiocarbaminate, 3-triethoxysilyl-propyl-N,N-diallyl-dithiocarbaminate, 4-trimethoxysilyl-butyl-N,N-diallyl-dithiocarbaminate, 3-triethoxysilyl-propyl-N-cyclohexyl-dithiocanbamate, 4-tripropoxysilyl-butyl-N,N-dicyclohexyl-dithiocarbaminate, 3-trimethoxysilyl-propyl-piperidino-dithiocarbaminate, 3-triethoxysilyl-propyl-morpholino-dithiocarbaminate, 3-triethoxysilyl-propyl-N,N-dibenzyl-dithiocarbaminate, 3-triethoxysilyl-propyl N-cyclohexyl-N-ethyl-dithiocarbaminate, 1,3-(3-N,N-diallyl dithiocarbaminato propyl)- 1,1,3,3-tetraisopropoxy disiloxane.

The new sulfur containing organo-organooxysilanes can be prepared in the manner disclosed below.

' Unless otherwise indicated all parts and percentages are by weight. I

. EXAMPLE I 3-thiocyanatopropyl triethoxy silane 272 grams of water free potassium thiocyanate were dissolved in 1500 ml. of dimethylformamide and heated to boiling. Then in the course of about 2 hours there were added dropwise 674 grams of 3-chloropropyl triethoxy silane. After a further 30 minutes heating the reaction according to the equation. NCS.K+Cl(CH -Si(OC H 4 NCS(CH Si(OC H +KCl was ended. After cooling the separated potassium chloride was filtered oil over a Seitz filter and after removing the solvent the 3 -thiocyanatopropyl triethoxy silane was finally recovered by vacuum distillation. B.P. 9798 C., yield about 85% based on the weight of the 3-chloropro- 6 pyl triethoxy silane. The yield can be further increased by optimizing reaction conditions.

Analysis.Ca1culated (percent): C, 44.70; H, 7.98; Si, 10.68; N, 5.31; S, 12.18. Found (percent): C, 44.80; H, 7.93; Si, 10.30; N, 5.35; S, 12.20.

The 3-thiocyanatopropyl triethoxy silane was further defined by its IR-spectra characteristics.

EXAMPLE II 3-triethoxysilylpropyl-ethyl-xanthogenate grams of potassium ethyl xanthogenate were dissolved in 500 ml. of acetone and 120 grams of 3-chloropropyl triethoxy silane were added dropwise to this solution. The mixture was stirred for 5 days at room temperature. After this time the reaction according to the equation 7 3-Si(OC1H5 was practically completed. The potassium chloride which precipitated was filtered 011 and the solvent removed by distillation. The yellow liquid remaining behind could not be distilled in vacuum without decomposition. Yield 82% based on the weight of the 3-chloropropyl triethoxy silane.

Analysis.-Calculated (percent): C, 44.12; H, 8.03; Si, 8.60; Cl, S, 19.64. Found (percent): C, 43.85; H, 8.23; Si, 8.40; Cl, 0.6; S, 18.65.

The reaction can also be carried out in ethanol as the reaction medium. In this case the sodium ethyl xanthw genate is advantageously produced in situ.

In 400 ml. of ethanol there were dissolved 23 grams of sodium metal, subsequently at 50 C. there were added 76 grams of carbon disulfide. After a short post reaction time there were added dropwise 241 grams of 3-chloropropyl triethoxy silane. After the end of the reaction the precipitated sodium chloride was filtered off and the mixture worked up as described above.

EXAMPLE III 3-thiocyanatopropyl tri-n-butoxy silane 24.3 grams of potassium thiocyanate were dissolved in 900 ml. of n-butanol and the solution heated to boiling. Then there were added dropwise in about 30 minutes 81.3 grams of 3-chloropropyl tri-n-butoxy silane. After a further 20 hours of boiling at reflux temperature the precipitated potassium chloride was separated otf with a Seitz filter. The solvent was distilled 011 from the filtrate and the 3-thiocyanato-propyl tri-n-butoxy silane distilled in vacuo. B.P. 128129 C., yield 85% based on the weight of the 3-chloropropyl tri-n-butoxy silane.

Analysis.Calculated (percent): C, 55.50; H, 9.49; Si, 8.20; N, 4.01; S, 9.20. Found (percent): C, 54.61; H, 9.26; Si, 7.90; N, 3.90; S, 9.00.

EXAMPLE IV Z-diethylamino-4-mercapto-6- (3 -triethoxysilylpropyl thiotriazine 27.1 grams of 2-diethylamino-4,6-dimercapto triazine were dissolved in 350 ml. of acetone and 15 grams of triethylamine were added as an HCl acceptor. Then the mixture was heated to boiling and in the course of 20 minutes there were added dropwise 30.1 grams of 3-chloropropyl triethoxy silane. After a further 20 hours the precipitated triethylammonium chloride was filtered off over a Seitz fi1ter.-The solvent was separated by distillation with the help of a vacuum. The reaction product is a crystalline mass which cannot be distilled even in high vacuum. Yield 94% based on the weight of the 3-chloropropyl triethoxy silane. The reaction product is apparent- 2 mercapto groups.

EXAMPLE IV a 1,3-(3-thiocyanatopropyl)-1,1,3,4-tetramethoxy I disiloxane 45.2 grams of sodium thiocyanate were dissolved in 300 ml. of dimethylformamide and the solution heated to 140 C. Then there were added in about 60 minutes 98 grams of 1,3-(3-chloropropyl)-l,l,3,3-tetramethoxy disiloxane. 'After a further 30 minutes heating the reaction was practically completed. After cooling the separated sodium chloride was filtered off over a Seitz filter and the solvent removed by vacuum distillatiomThe liquid remaining behind was l,3-(3-thiocyanatopropyl)-1,1,3,3- tetramethoxy disiloxane. Yield 95% based on the Weight of the 1,3 (3 chloropropyl) 1,l,3,3-tetramethoxy disiloxane.

Analysis.-Calculated (percent): C, 36.34; H, 6.10; Si, 14.16; N, 7.06; S, 16.12. Found (percent): C, 36.20; H, 6.02; Si, 13.97; N, 7.10; S, 15.95.

The 1,3-(3-thiocyanatopropyl)-1,1,3,3-tetramethoxy disiloxane was further defined by its IR-, NMR- and massspectra.

It is already known that 3-mercaptopropyl trimethoxy silane when used in natural rubber-silica mixtures reduces the strength of the crude mixture and raises the modulus values of the vulcanizates considerably as well as their rebound and shore hardness.

On the contrary the working properties of the mixtures are disadvantageously influenced, for example, the scorch time is greatly shortened. This means a reduction of the working safety. Further the Defo elasticity (see following Table I) is greatly increased which indicates an increase in the elastic rubber portion in the crude mixture and results in increased difficulties in their further working, for example, in extruding processes. On the contrary it has now been found that the compounds of the invention on the one hand extensively produce the advantages of 3-mercaptopropyl trimethoxy silane but on the other hand more favorably influence the working properties of the rubber-filler mixtures. Furthermore, many of the compounds of the invention are ac cessible in a very economical manner because of their simple process of production with good yields and the ready availability of the starting materials and in addition are excellent for industrial duty.

A process is already known for the production of organosilicon sulfides wherein, among others, halogen-ethyl alkoxysilanes are reacted with alkali metal or alkaline earth metals salts of organic sulfides or sulfidic comfpounds (German Oifenlegungsschrift 1,911,227). The compounds produced in this manner can be used as adhesive means or as intermediates for the production of water repellent agents or oxidation inhibitors. i

The sulfur containing organo-organooxysilanes can be added directly, for example, to the rubber mixture. In this connection it is not necessary to hydrolyze the organo-organooxysilanes before the addition. Apparently, themoisture present in the mixture causes a partial hydrolysis which, for example, is necessary in the presence of silica containing compounds or silica fillers to produce siloxane bridges or in the presence of other inorganic materials in the starting mixture for building other bonds, for example, oxygen bridges through the splitting out of water from hydroxyl groups.

The sulfur containing organo-organooxysilanes can, however, with advantage must not be used coated on inorganic materials, for example, as fillers which means a process advantage,

,Advantageously the inorganic fillermaterial can beza mixture of at least two different rubber reinforcing fillers, e.g., silica and carbon black. The inorganic filler material may be introduced into the composition per se or pretreated with thesaid sulfur containing organo-organooxysilanes, e.g. coated with the sulfurcontaining organo-or ganooxysilanes or the filler material, maybe sprayed or dusted with said sulfur containing organo-organooxy silanes.

EXAMPLES v TO III A I Testmii-rture 1 2 5L 6 Amounts in partsby weight:

Styrenebutadiene rubber (Type 1500) Precipitated silica (Ultrasil VN3).-. Zinc oxide Stearic acid Dibenzothiazyldisulfide Diphenylguanidine Sulfur 3-mercaptopropyl trimethoxy silane (according state of the art) Example V-3-thiocyanatopropyl triethoxy silane Example VI-3-thiocyanatopropyl tri-n-butoxy Q Q P Example VII-3-trlethoxysilylpropylethylxsmth nap are Example VIII-2-dietliyl- I amino-4-mercapto-6- 1- (3-triethoxysilyli propyl) -tl1iotriazine 1 5 Test results: 1

Defo hardness, (g.) 3, 050 2, 200 1,950 2, 250 1,900 '2, 300

Defo elasticity, percent- 16 33 21 22 29 Mooney-scorch time 3 n (m1n.) Mooney-cure time 3 min. Tensile strength 4 kpJcmfl) Modulus 300% 4 (kp./cm. Elongation at break 4 Rebound, percen l Shore hardness 74 74' 73 73 Permanent extension, 1

percent 14 8 7 7 7 7 l The vulcanization of the mixture took place at 160 C. and'the Vul-i canization time was 40 minutes. 1 V

2 Determined according to German industry standards (DIN) 53514:

B Determined according to DIN 53524 (the Mooney scorch t me is also designated as pre-vnlcarnzation time ty, and the Mooney cure tame as prevulcanization time tas).

4 Determinedaccording to DIN 53504.

5 Determined according to DIN 53512.

Determined according to DIN 53505.

7 Measured one hour after tearing the DIN 53504) ring (ring tearing method;- see The reduction of the Defo hardness of the testmixtures 5 to 8 (Table I) isabout one-third as comparedto mixture 1 and points ,to their easier workability. H

.The increase in modulus to more than double that of the blank is related to a high degree of crosslinking.

The increase in rebound compared to the blank indicates more favorable dynamic properties. The increase of the Shore hardness compared to'the' blankcan otherwise frequently only be attained by increase in the portion of filler in the mixture. I

Finally, the reduction of theperrnanent extension compared to the blank is interpreted as animportant improve: ment of the performance properties, x

Compared to test mixture No. 2 (state of thear't) there is shown a definitely more favorable relation withregard to the Defo elasticity and pre-vulcanizationtime t as'well as t which makes it substantially easier or first makes it p0 sible to handle such a mixture in the plant. v

EXAMPLE IX It is known that zinc oxide and stearic acid are ab- SOIutely required to vulcanize rubber-silica mixtures. The

action of 3-thiocyanatopropyl trimethoxy silane ina mix-1 ture free of zinc oxide and stearic acid is shown in the following. I t- TABLE II Testmixture 9 --10 Styrene-butadiene rubber (Type 1500) 100 I 100'. Precipitated silica (Ultrasil VN3).-. 40 1 40 Diben'zothiazyldisulfide 1. 5 11 5 Diphenylguanidine--- 1.5 Sulfur 2. 75 B-thioeyanatopropyl trimethoxy silane 1. 5

TEST RESULTS Defo hardness (g.) 2, 900 2, 000 Defo elasticity (percent) 25 22 Mooney-scorch time (min. j 11 11 Mooney-cure time (min.) 7 15 15 Tensile strength (k .lcmfi) 153 1 168 Modulus 300% (kp. cmfi) 73 144 Elongation at break (percent)- 425 330 Rebound (percent);..- 42 44 Shore hardness 72 75 Permanent extension (percent) 12 7 No'rE.'lhe vulcanization was carried out at 160 C. and the vulcanization time was 60 minutes. p p

The measurements were made, as in1ExairrplesfV to VIII (Table I). The advantages of test mixture 10 are essentially equal to those in. the previous examples.

EXAMPLE X To determine whether the sulfur containing organo-organooxysilanes of the inventionare -also"suited for use after they have previously been contacted with the filler 3-thiocyanatopropyl trithoxy silane as a test substance was dissolved in ethyl alcohol; then the-.Ultrasil VN3 was introduced into the solution and finally the solvent was removed. The proportions were so chosen thatexactly 40 parts of Ultrasil VN3 and 1:.5'parts'of.'3 thiocyanatopr pyl triethoxy silane were present in both mixtures. The test took place with the same mixture and in thesame manner as'is'given in Table I. 3

In the test mixture 11, however, the Ultrasil VN3 andthe 3-thiocyanatopropyl triethoxy silane were mixed in separately, in the test mixture 12 on the contrary therewas used Ultrasil VN3 loaded with the 3thio'cyanatopropyl triethoxy silane (produced asset forth above).

TABLE III.--TEST VRQESULTS Test mixture 11 12.

Date hardness (g.) L. 2, 150 2, 200 Defo elasticity (percent) 23 20: Mooney-scorch time (min.) 17 17, Mooney-cure time (min.) 20 21 Tensile strength (k ./cm. 144 152 Modulus 300% (kpjcmfl) 116 1 115 Elongation at break (percent) 340 365 Rebound (percent) 45 44 Shorehardness 72 73 Permanent extension (percent) 7 9 From these values it is evident that there can be employed with success the previous coating of a silica filler with 3-thiocyanatopropyl .triethoxy silane.

EXAMPLE m The activity of 3-thiocyanatopropyl tri -n propoxy silane is shown in the following natural rubbierlmixture containing Aerosil, i.e. pyrogenic silica. The amounts are given in parts by weight. The measurements were made in the same manner as in Table I.

TABLE IV Test mixture. 13 14 Ribbed smoke sheets I 100 Aeros1l(130 rnJ/g. BETsuriaee) 40 40 no oxide 4 4 Steari arid I 2 2 Dibenzothiazyldisulfide 1. 5 1. 5- Diphenylguanidine 1. 5 1. 5- Sulfur. 2. 75 2. 75 a-thiocyanatopropyl tri-n-propoxy silane 1. 5

TEST RESULTS Defo hardness (g.) 2, 300 1, 650 Deio elasticity (pereent)-- v 29 24 Mooney-scorch time (min 18 13 Mooney-cure time (min.)- 21 15 Tensile strength (k ./cm. 26 4 284 Modulus 300% (kp. emfi) 670 600 Rebound (percent) r -52 56 Shore har 64 66 Nora-.The vulcanization was accomplished at C. and the vul canization time was 20 minutes.

i There was obtained with natural rubber and a pyro- The starting mixture (test mixture 15) was composed of the following'Qconstit-utents (in parts by weight).

StyreIie-but'adiene rubber (Type 1500) 100 Ultrasil VN3 40 Zinc oxide r 4 Ste'aric acid 2- 3-thiocyanatopropyl triethoxy silane -Q 3 Sulfur vulcanization time was 60 minutes and the following test results wereobtained. v

Modulus 300% (kp./cm?) Modulus 500% (kp./cm?) Elongation'at break (percent) 670 Rebound (percent) 40? Shore hardness The new sulfurcontaining organo-organooxysilanes, as

. stated, in the widest sense areoutstandingly useful in link-ab mixtures of organic polymers, inorganic, ma-

teirialsfand. c ro sslinking agents there can be added in giyen case known reaction accelerators and furtherrr iori' i i afgive'ri'ca'se one or more compounds of the groupoff' antioxidants (antiagers), processing-aids, plasticizers and heat or light stabilizers which are known in plastic tech nology. For vulcanization thereare added to the mixture vulcanization agents, especially sulfur and/or sulfurlibcrating compounds, e.g. N,N'-dithiobis morpholine, dipent'famethyl'ene' thiuramtetrasulfide, N,N-dithiobis hexaliydro 2H a'zepinone-(2), Z-b'nzthiazyl dithio-N-morpholide'etc. and in a given case ofvulcanization accelera-' tors; additionally therecan be included and homogeneously=-' distributed in these mixtures one or moreflcom-w pounds O..the-; gr oup of rubber antioxidants processing;

The vulcanization was carried out at C,

aids, pigments and stearic acid as well as zinc oxide which all are known and used in the rubber art. The sulfur containing organo-organooxysilane manifestly acts in the crosslinking or vulcanization reaction.

It is evident to those skilled in the art that compounds of the class A(b) which contain the thioether group must contain one or more additional vulcanization active groups as for example the 2,4-dimercapto-1,3,5-triazinyl group and/ or one or more additional vulcanizable groups as for instance the allyl group or other groups having nonbenzoid carbon to carbon unsaturation.

The named inorganic materials can be added as fillers, pigments, fibers or the like. Of especial advantage in this regard there are preferably added as inorganic filler materials substances which are designated in the rubber industry as reinforcing fillers. These preferred additives are especially based on silica of various Origin or such silica (silicon dioxide) containing oxide mixtures and mxed oxides, namely oxide compounds of metals such as aluminium, magnesium, calcium, barium, zinc, iron, zirconium or titanium, e.g. alumina, magnesium oxide, calcium oxide, barium oxide, zinc oxide, ferric oxide, zirconia, titania, aluminium silicate, talc, asbestos etc. including oxides (mixed oxides) of two or more of said metals.

Those oxide compounds which are also designated as highly dispersed or finely divided materials are preferably produced in the gas phase by oxidative or hydrolytic decomposition, namely emanating from volatile metal or metalloid halogenides. Also well suited are those obtained by precipitation of a soluble compound of the above named elements, e.g. of a soluble silicate. In a given case there also can be employed as the inorganic materials natural silicates or silicates produced chemically such as asbestos, wollastonite, kaoline, talc as well as quartz, sand, clay, carbon black or the like or glass in the form of fibers, mats, fabrics or other fiber products or structures as well as compact varieties or metal fibers, e.g. aluminium or steel fibers.

The new sulfur containing organo-organooxysilanes have valuable properties; they possess in the sense of the present invention bifunctional activity. The new oxysilanes promote, for example, the vulcanization or crosslinking of elastomer or rubber mixtures. Even without addition of conventional accelerators or activators there are obtained with the compounds of the invention at the customary crosslinking or vulcanization temperatures and times vulcanizates with normal use and test data. They also act as coupling agents. The binding (coupling) capacity, for example, to silica or silicate surfaces occurs through the trialkoxysilane group by chemical reaction forming Si--OSi bridges or by chemisorption. This binding property is also true of the compounds of group A(b) of the invention.

The activity of the sulfur containing organo-organooxysilanes is especially advantageous in rubber mixtures for the production of tires which contain the so-called light reinforcing fillers, also they develop valuable prop erties in tire production using glass fibers, yarn, cloth, fiber quilt or similar structures, wherein there are employed, for example, styrene-butadiene rubber, butadiene rubber, natural rubber, cis-isoprene rubber or the like elastomers. Thus it is possible for example to produce white or colored tires or tire treads with the help of the new compounds from rubber and light reinforcing fillers. Among the usable types of rubbers there should also be included the usual known diene rubbers, nitrile rubbers, terpolymers, for example, of ethylene, propylene and dienes or trienes etc.

- The sulfur containing organo-organooxysilanes can be added in an amount of 0.1 to 20%, preferably 0.5 to based on the weight of the organic polymer.

For the vulcanization of the rubbery polymers there can be added sulfur and/or sulfur liberating compounds in an amount of 0.2 to 4 weight parts per 100 weight 12 parts of the rubbery polymer of the types mentioned above.

The inorganic filler material can be added to the mixtures (compositions) in an amount of 5 to 100 parts by weight (preferably 10 to parts by weight) per parts by weight of said rubbery polymers. These compositions may include 2 to 5 parts by weight of zinc oxide and 0.5 to 3 parts by weight of an accelerator.

What is claimed is:

1. A composition comprising an ethylenically unsaturated vulcanizable rubber, an inorganic filler material, at least one member of the group consisting of sulfur and a sulfur liberating substance and a sulfur containing organoorganooxysilane of the formula A-XZ where X is either (1) a divalent acyclic or cyclic hydrocarbon group having at least 3 carbon atoms in the main chain and when cyclic not over 18 carbon atoms, (2) or such a cyclic hydrocarbon having a hydrogen replaced by fluorine, pseudohalogen, phenyl, halophenyl, monoalkyl or dialkyl phenyl in which the alkyl contains 1 to 3 carbon atoms; and

where R and R" are alkyl of 1 to 12 carbon atoms.

2. A composition according to claim 1 wherein X is alkylene of 3 to 18 carbon atoms.

3. A composition according to claim 1 wherein X is alkylene of 3 to 5 carbon atoms.

4. A composition according to claim 1 wherein Z is Si(OR) 5. A composition according to claim 1 wherein R is alkyl of Ho 4 carbon atoms.

' 6. A composition according to claim 1 where X is alkylene of 3 to 5 carbon atoms, Z is Si(OR') and R is alkyl of 1 to 4 carbon atoms.

7. A composition according to claim 1 wherein it contains a vulcanization accelerator.

8. A composition according to claim 1 wherein the inorganic filler material is a rubber reinforcing filler.

9. A composition according to claim 1 wherein the inorganic filler material is a mixture of at least two different reinforcing fillers.

10. A composition according to claim 8 wherein the filler is a metal oxide or a metalloid oxide.

\ 11. A composition according to claim 8 wherein the filler is a finely divided oxide, mixed oxide or oxide mixture of at least one member of the group of elements consisting of aluminium, silicon and magnesium.

12. A composition according to claim 1 wherein the inorganic filler material is silicate glass or quartz.

13. A composition according to claim 1 wherein the rubber is a butadiene homopolymer, an isoprene homopolymer, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer or ethylene-propylene-polyene terpolymer.

14. A composition according to claim 1 wherein the inorganic filler material is a material pretreated with said organo-org-anooxysilane.

References Cited UNITED STATES PATENTS 3,567,680 3/1971 Iannicelli 26041.5 A 3,350,345 10/ 1967 Vanderbilt et al. 260-41.5 A

LEWIS T. JACOBS, Primary Examiner 

